Thread Tools
May 30, 2019, 01:51 AM
Julian T
I agree with most of jbeech's comments. However, some of the better and more powerful becs come with 2 power leads to the rx so taking you into 10A territory. That includes some built in becs, e.g. Hobbywing and Jeti Mezon ESCs. I would also suggest it is foolish to not take steps to ensure your servos do not stall by ensuring your geometry is correct for the setup and the servo is adequately specified for the task. Of course the start up current on a digital is going to be high but I assume should still not reach stalled peaks, at least for more than a milli second or two.

In my experience these setups have been fine in 3D models up to 60" and 2M pattern models. Direct battery connections are fine of course but they do come with the disadvantage that voltage varies with pack charge state. With an adequately specced BEC my telemetry logs show zero rx voltage fluctuation over a flight.

YMMV of course!

Julian
Sign up now
to remove ads between posts
May 30, 2019, 06:30 AM
Anthony . . . I won't step into the ESC wars, sorry. Me? Right now I'm playing with a 48" instead of a 52" (4S2700 vs 4S3300 propulsion pack and you can tell the difference). For 'my' skill level (accomplished sport pilot but totally a 3D beginner), a 550-1000mAH pack is fine - but - we have packs going down to 250mAh. Note, the 250mAh masses 16g and the 1000 masses 55g. So let's talk theory vs. practice. In theory, for maximum performance, you want the lightest pack - no question. Thus, you size the pack (capacity) to be just enough to complete a flight. A 250mAh pack is plenty for a flight or two. HOWEVER, in practice, charging the avionic pack after every flight is rather less than convenient (but make no mistake - this is the optimum set up).

So in the real world and taking into account my skill level plus my opinion that nobody can really tell the difference between a 16g ($15) and 55g ($20) pack in flight (especially if care is taken to located it such that the CG is unchanged between them), then a pack large enough to complete all the flights in a day is fine by me. But take note, I don't pretend to be a big dog, which is why a single lead $17 pack (29g 550mAH) suits me in planes like a QQ Extra or a 48" Extra from EF because I'm not exceeding 5A. But yes, I might go to a 1000mAh pack with a 52" because the servos can draw more, but I might also be perfectly happy with the 550 in a 52" because I'm not pushing the envelope. Pick your poison. Wishy washy answer? Yes, know but it's because the real answer is . . . it depends.

Julian . . . if you eyeballed BEC output on an oscilloscope I believe you'd change your opinion. Anyway, adding another lead to the BEC is a perfectly viable way to achieve more than 5A into the receiver, I totally agree with you.
May 30, 2019, 03:31 PM
Registered User
Trill's Avatar

All the right stuff


John,

Thanks for your timely reply.

So, how many five minute flights will I get out of your Battery, LiPo, 2S1000-35C and four DS150CLHV servos in an EF 52" Slick EXP equipped with an Aura 8 and XXX brand ESC?

Yes, it depends, but an approximation such as "perhaps at least three flights or perhaps as many as five flights" lets me know whether I need a smaller or larger battery.
Last edited by Trill; May 30, 2019 at 03:47 PM.
May 30, 2019, 05:34 PM
I don't have a clue. Maybe five flights but honestly, that's a SWAG.

Fortunately, and unlike NiCds and other chemistries, LiPo packs can be measured at rest with a cheapo VOM (Volt-Ohm-meter) where DC voltage will indicate what percentage of charge the pack is (e.g. capacity). Learn a bit more here . . .
http://www.promodeler.com/askJohn/Ho...for-LiPo-Packs
. . . and feel free to print the chart, laminate it, and stick it under a rear floor mat of your car to keep handy.
Last edited by jbeech; May 30, 2019 at 05:42 PM.
May 30, 2019, 05:49 PM
Registered User
Trill's Avatar

Righto!


John,

Thanks again.
Jun 15, 2019, 06:35 PM
Team Extreme Flight
Doc Austin's Avatar
This plane just keeps getting better and better.

(4 min 38 sec)
Jun 15, 2019, 11:37 PM
I am not a robot
Sideslip's Avatar
Nice Doc. Yeah the plane flies very nice. But you got quite a bit to do with that.
Jun 16, 2019, 08:26 AM
Funny thing is, when pressed, Doc says he actually likes the 48" wingspan models even more! Can you believe that? Me? I've always hewed to the mantra bigger flies better so I never thought I'd ever hear this from a pilot. However, combine the incredible airframes coming from Chris and company, plus the various available gyros that simultaneously give you the big airplane feel, and couple it with servos that help you take advantage of these benefits then suddenly we're onto something new in model aviation. New things are rare. Finally, regarding Doc, is he a good pilot? Well, duh, of course he is - but - we're in danger of missing the bigger picture here. My take is Doc's commenting on things even an average guy, can take notice of. Basically, he's conveying the news that there's something new afield.
Jun 16, 2019, 08:45 AM
3D Addict
alfabeast's Avatar
Another way to get 2 power leads into a receiver is to use the high end futaba switch that has 1 deans plug in and 2 regular leads out. Using on my 7x planes and a 2s 2600 lipo

FUTM4391 Is the part number
Jun 16, 2019, 09:57 AM
That Futaba is a good switch, I agree with your decision to deliver more than 5A into the receiver - well done. However, and not to come off as argumentative on this forum (especially because I've probably said this before) but relying on a single switch gives me the willies.

Basically, I favor two inexpensive switches over pretty much any pricey solution that relies on one switch. Why? Simple, it's because odds of both failing on the same flight are astronomical.

Bottom like? This also gets me 10A into the receiver but for significantly less cost (just the one Futaba switch is $30). And please note; my point isn't to try and sell you our heavy duty switch because we - along with many other - offer these simple mechanical switches. Two witches in parallel are the gold standard in my opinion.

Anyway, if you poke around on our website you'll dicover they're just $10 - but switches, extensions, and battery packs are things we principally offer as a matter of convenience. E.g. they're not our main line business so we make little effort to 'push' the fact we make them available. About the only thing to look out for when buying a switch is the difference between the standard switch ad the heavy duty. Finally, I have ours made with 20AWG wire. The point being these switches are a little more capable than the average switch in a hobby shop and the wire is considerably more capable but they weigh a tad bit more than a ordinary switches built with lighter gauge wire (but that's a minor thing in the grand scheme of things - especially for a 7x model).

Anyway, as you've shared, there's more than one way to skin a cat.
Jun 16, 2019, 11:20 AM
Team Extreme Flight
Doc Austin's Avatar
Quote:
Originally Posted by jbeech
Funny thing is, when pressed, Doc says he actually likes the 48" wingspan models even more!
Oh, the 52s have become my favorite, but lately I have been waffling on that. The 52s do fly better, but the 48s are so practical and affordable that scores a lot of points. That, and as you know, I've been testing some new equipment that really changes the game in 48" planes.

I think with the Extra V2 (and hopefully more) coming soon, the 48s will be more viable and desirable than ever. There has not been a new 48 in four or five years, but they continue to sell extremely well and run out of stock often. In a hobby where everyone has to have the latest and greatest of everything, anything that stays on the market that long must be pretty damm good. I think the V2 treatment will assure the 48" Extra will continue as the 4ft benchmark for another 10 years, and I also think the entire lineup will have a new lease on life.

Quote:
However, combine the incredible airframes coming from Chris and company, plus the various available gyros that simultaneously give you the big airplane feel, and couple it with servos that help you take advantage of these benefits then suddenly we're onto something new in model aviation.
The last two years have completely obsoleted the equipment we were using. At least for me, there is no going back.

My observation is the smaller you go with a plane, the more an ESS helps. On a 60", it's awesome, and on a 52", a gyro is utter magic. On a 48", it's more like the parting of the Red Sea. With ESS units now having almost universal approval, and with more guys ready to try them, all the 48s are going to be so much better than ever.

Where the 48s needed a little help was with servos. Now that I have had a few weeks testing some super gold plated mega magic uber wonder servos in one of my beloved 48" Extras,, my enthusiasm for the 48" class is very much renewed. Now that plane flies more like a 60", and you don't have to believe me........just check the latest videos.

Like I said, we needed a little servo help and instead we got a lot. My 48" Extra has been my primary plane for about 10 years and I know it extremely well. I had already tested the plane extensively with an ESS and really liked the difference, but even at that I truly thought there were zero surprises left in the old girl. After a single flight with the new servos my thinking on the 48s changed.

The 48" Extra was so far ahead of it's time that it took this long for the equipment to catch up. I wish all of you could take a lap with my 48 Extra the way its equipped right now. As many thousands of flights as I have had on 48" Extras, I never dreamed they could be this good. It's like driving Porsche for 10 years and then discovering the button that gives you another 200 hp.

In the end, it's a Synergistic Integration kind of thing. It's a matter of all the components working together to take everything to the next level. We started with the perfect airframe, and used the prefect ESS to gain even more stability, and soon we will have a dead perfect centering servo with enough torque to sink the Bismark, Tirpitz and Yamato all at once. You put all that stuff together and it's going to be the best thing you've ever flown. Add to that the V2 itself is going to be a solid performance leap, and it could get pretty crazy.

Quote:
My take is Doc's commenting on things even an average guy, can take notice of. Basically, he's conveying the news that there's something new afield.
As an average guy, that's kind of my niche!

The big news is the V2 Extra signals that the 48" class is not going to be put out to pasture and we might even get some more. That, right there, is huge, and with ESS units gaining nearly universal acceptance, even the V1 is flying better than it ever has. Where the 48s needed help was with servos and pretty soon we will have that in a bigger way than we could have hoped for.

For the next week or so I will be concentrating on the new Velox because I still have to write a flight report and get more video, but after that super gold plated mega magic uber wonder servo testing will resume. Production is kind of out of my hands, but I am hoping that happens before the V2 gets here.
Jun 16, 2019, 12:58 PM
3D Addict
alfabeast's Avatar
Quote:
Originally Posted by jbeech
That Futaba is a good switch, I agree with your decision to deliver more than 5A into the receiver - well done. However, and not to come off as argumentative on this forum (especially because I've probably said this before) but relying on a single switch gives me the willies.

Basically, I favor two inexpensive switches over pretty much any pricey solution that relies on one switch. Why? Simple, it's because odds of both failing on the same flight are astronomical.

Bottom like? This also gets me 10A into the receiver but for significantly less cost (just the one Futaba switch is $30). And please note; my point isn't to try and sell you our heavy duty switch because we - along with many other - offer these simple mechanical switches. Two witches in parallel are the gold standard in my opinion.

Anyway, if you poke around on our website you'll dicover they're just $10 - but switches, extensions, and battery packs are things we principally offer as a matter of convenience. E.g. they're not our main line business so we make little effort to 'push' the fact we make them available. About the only thing to look out for when buying a switch is the difference between the standard switch ad the heavy duty. Finally, I have ours made with 20AWG wire. The point being these switches are a little more capable than the average switch in a hobby shop and the wire is considerably more capable but they weigh a tad bit more than a ordinary switches built with lighter gauge wire (but that's a minor thing in the grand scheme of things - especially for a 7x model).

Anyway, as you've shared, there's more than one way to skin a cat.
Hi, yes, I too am an obsessive risk mitigator. I have run 2 packs with 2 cheaper switches, but I figure hey, it's a Futaba - just making real careful there are no loose wires or any other things that could some how snag it. Next time I get some servos I'll get some Rx packs from you on the same order and the thicker short extensions to get rid of switches completely. I did almost take out a greenhouse with a runaway Quickie 500 at full throttle in a series of huge loops due to a Hobbico switch failing one time. I'm sure we would have lost the field on that one!
Jun 23, 2019, 08:29 PM
Registered User
Trill's Avatar

Righto!


Quote:
Originally Posted by Doc Austin
This plane just keeps getting better and better.

Better to best!

Doc,

Which servos are you using in the yellow 52" Slick EXP in the video?

Will you switch to a 2S lipo to power the servos?
Jun 23, 2019, 08:51 PM
Team Extreme Flight
Doc Austin's Avatar
Quote:
Originally Posted by Trill
Which servos are you using in the yellow 52" Slick EXP in the video?
DS100. It flies so good I never bothered to upgrade to DS150

Quote:
Will you switch to a 2S lipo to power the servos?
Probably not.
Jun 23, 2019, 09:10 PM
Registered User
Trill's Avatar

2S lipo in the 52" planes


Quote:
Originally Posted by Doc Austin
Probably not.
Yes, in the 52" planes I'm comfortable/satisfied with a high quality ESC. It's not worth my time and the extra wires to use a 2S lipo in the "smaller" planes.

Also, balancing the plane and extra weight could be problematic. Better for me to go with a proven set up.


Quick Reply
Message:

Thread Tools